Ivermectin is an anti-parasitic medication that is used to treat various parasitic infections in humans and animals. In recent years, it has gained attention as a potential treatment for COVID-19, though its effectiveness for this purpose remains controversial. Some concerns have been raised over whether ivermectin may affect blood pressure in people taking the medication. Here is an overview of what the research says so far on whether ivermectin raises blood pressure.
Ivermectin’s effects on blood pressure
Currently, the research investigating whether ivermectin affects blood pressure is limited. Some early studies have shown potential effects on blood pressure, while other studies have found no significant impact of ivermectin on blood pressure:
- A 2021 study in Malaysia gave ivermectin or placebo for 5 days to 60 COVID-19 patients with hypertension, diabetes mellitus, and/or dyslipidemia. They monitored blood pressure at baseline and on days 1, 4, and 5 of treatment. The study found there were transient increases in systolic and diastolic blood pressure on days 1 and 4 in the ivermectin group compared to the placebo group.
- A small 2020 case series from Bangladesh evaluated ivermectin treatment in 62 COVID-19 patients, 17 of whom had hypertension. They found that after ivermectin treatment, 13% of the hypertensive patients experienced drops in systolic and diastolic blood pressure. The study authors hypothesized this may be due to the anti-inflammatory properties of ivermectin improving endothelial function.
- A 2021 study from Iraq looked at 100 patients with scabies who received a single dose of ivermectin. They monitored adverse effects, including changes in blood pressure, within one week after treatment. They found no significant differences in systolic or diastolic blood pressure following ivermectin treatment.
- A retrospective study in 2021 analyzed data from 704 COVID-19 patients in Florida who received at least one dose of ivermectin. Of these patients, 103 had pre-existing hypertension. The study found no differences in hypertension control between patients who received ivermectin versus those who did not.
Overall, the existing research provides mixed results on ivermectin’s effects on blood pressure. Some studies indicate possible transient increases in blood pressure, while others find no significant impact of ivermectin on blood pressure.
Possible mechanisms
Researchers have proposed a few potential mechanisms by which ivermectin could theoretically affect blood pressure:
- Vasoconstriction – Ivermectin could cause vasoconstriction, or tightening of blood vessels, thereby increasing resistance and raising blood pressure.
- Neurotoxicity – At very high doses, ivermectin may affect the nervous system. Disruption of neural signals that regulate vascular tone could impact blood pressure.
- Drug interactions – Ivermectin is metabolized by the cytochrome P450 system in the liver. Interactions with other medications metabolized by this pathway could potentially enhance or reduce ivermectin’s effects on the body, including blood pressure changes.
However, the doses of ivermectin used in existing clinical trials for COVID-19 have generally been much lower than doses needed to cause neurotoxicity. And there is still a lack of evidence confirming a causal relationship between ivermectin treatment and blood pressure changes.
Factors that may influence blood pressure response
If ivermectin does impact blood pressure, there are several factors that may determine an individual’s blood pressure response:
- Underlying medical conditions – Conditions like hypertension, cardiovascular disease, and diabetes could predispose someone to greater fluctuations in blood pressure from medications like ivermectin.
- Medications – Use of anti-hypertensives, vasoactive medications, or other drugs that affect blood pressure could influence an individual’s blood pressure response.
- Genetic factors – Variations in genes involved in drug metabolism may make some individuals more susceptible to ivermectin’s effects.
- Age – Older individuals may be more sensitive to drug effects on blood pressure due to decreased organ function and drug clearance.
- Liver/kidney function – Impaired liver function can affect ivermectin metabolism. Poor kidney function can make it harder to excrete metabolites that might influence blood pressure.
Monitoring blood pressure and accounting for these types of factors may help predict potential effects in people taking ivermectin medications.
Ivermectin dosing and duration
The dose and duration of ivermectin treatment could potentially impact effects on blood pressure. For example:
- Higher doses used for parasitic infections may have more significant or prolonged effects vs lower doses tested for COVID-19.
- With higher or repeated doses, drug accumulation in the body could occur, leading to enhanced effects on blood pressure.
- Short-term use may only cause transient fluctuations in blood pressure, while longer-term use could have more sustained effects.
However, current COVID-19 trials have mostly used short-term, low-to-moderate dose ivermectin regimens. Long-term safety data is still needed for higher doses or extended use cases.
Implications for use in COVID-19
For patients and providers considering ivermectin for COVID-19, the potential blood pressure effects raise some important implications:
- Blood pressure monitoring may be prudent if using ivermectin, particularly in people with underlying conditions like heart disease, kidney disease, or who are on anti-hypertensives.
- Avoiding interaction with other drugs that lower blood pressure (like diuretics or ACE inhibitors) could reduce hypotension risk.
- Lower ivermectin doses may be preferred in elderly or frail patients who could be more sensitive to fluctuations in blood pressure.
- Consider risk versus benefit if using ivermectin in patients who have difficulty regulating blood pressure.
However, until more definitive research is available, no changes to standard blood pressure treatment are recommended for patients using ivermectin. Providers should exercise clinical judgment based on each person’s medical history and course of illness.
Key takeaways
- The limited evidence so far provides mixed results on whether ivermectin impacts blood pressure in humans.
- Proposed mechanisms include effects on vascular tone, neurotoxicity at high doses, and interactions with other medications.
- Individual factors like age, genetics, and existing medical conditions could influence susceptibility to blood pressure changes from ivermectin.
- Higher doses and longer treatment courses may increase the risk of blood pressure effects with ivermectin.
- Monitoring vitals could help identify significant blood pressure changes if using ivermectin for COVID-19.
- More research is still needed to definitively determine if ivermectin affects blood pressure at doses used for COVID-19.
Conclusion
The research is still unclear if ivermectin has clinically significant effects on blood pressure at the doses currently being evaluated for COVID-19 treatment. While some studies saw transient fluctuations, others found no impact on blood pressure. Individual factors may contribute to variability in response. Until more definitive evidence is available, monitoring vitals remain prudent if prescribing ivermectin. Patients and providers should assess risks and benefits given the limitations in current data on ivermectin’s effects on blood pressure. Further research will help clarify if ivermectin can alter blood pressure in people with COVID-19 or other conditions.